Ed Davey said he was keen to set a decarbonisation target for the power sector, but how it was done is 'critical'. Photograph: Richard Saker for The Observer

Energy and Climate Change Secretary Ed Davey has hinted at plans for a "flexible" decarbonisation target for the power sector, which would help ensure the UK meets its legally-binding climate change targets for 2050.

The Liberal Democrats last week backed a motion at its party conference calling for an emissions target of between 50g and 100g of CO2 per kWh to be set for the power sector in 2030 as part of the Energy Bill.

However, the target remains the subject of fierce debate within Whitehall, with sources suggesting Chancellor George Osborne is opposed to the target on the grounds that he fears it will undermine investment in new gas capacity.

It currently remains unclear whether the target will be introduced in the Energy Bill, delivered through secondary legislation, or shelved altogether.

Speaking to BusinessGreen on the sidelines of the opening of the new E.ON and National Grid combined heat and power project in Kent on Thursday, Davey said he was keen to set a decarbonisation target, but wanted the final target to take account of the long-term legally-binding target to cut emissions by 80 per cent by 2050 in the UK.

"There's a very strong argument in my view that, because the power generation [sector] is an enabler for other sectors to decarbonise, such as transport and heating, we give additional support and encouragement to investors in low carbon energy," said Davey.

"There are a number of ways you can do that. One of the ways I think is attractive is a decarbonisation target for the power sector. But how we do that is obviously critical."

The Climate Change Committee has recommended that the most effective way to achieve the 2050 target would be to ensure electricity is produced at no more than 50g of CO2/kW by 2030. However, the current draft Energy Billl stops short of including such a goal.

Davey hinted the bill could include a target range, rather than a specific decarbonisation figure, arguing that such an approach would allow for greater flexibility based on the pace of development of low carbon technologies.

"The range that we aim for and how we ensure there's flexibility in that to take account of technology changes and so on, all has to be looked at and discussed," he said. "That will be discussed across government."

BusinessGreen has also learnt that a leading energy lawyer working with Friends of the Earth has drafted an amendment to the Energy Bill that would stipulate a 50g of CO2/kWh target, but allow for flexibility within the context of the overall 2050 carbon target.

Friends of the Earth maintains that a flexible carbon target could be included in primary legislation, for example, that would allow for other sectors, such as transport to make new advances in low carbon technology, which would in turn reduce the need for complete decarbonisation in the energy sector.

"A decarbonisation target would provide greater clarity on the direction of travel for many renewable energy businesses after 2020," said Donna Hume, energy campaigner for Friends of the Earth. "It would also ensure it was a more democratic and transparent process."

However, she warned that adopting a decarbonisation "range" instead of a specific target could result in the UK failing to deliver the necessary emissions cuts, and urged the government to ensure that a clear target is included in primary rather than secondary legislation.

"When we spoke to Ed Davey at the Lib Dem annual conference, he told us that he would be fighting for a 2030 decarbonisation target, which was great to hear," she said.

"But if the target, or range, is included in secondary legislation, there are more caveats and it could be more easily weakened."

Sign up for the Guardian Today

Our editors' picks for the day's top news and commentary delivered to your inbox each morning.

The Guardian Environment Network brings together the world's best websites focusing on green topics. The network connects sites from across the globe that provide high-quality news, opinion, advice, blogs, data and tools